In a general point-to-multipoint (P2MP) wireless communications network, such as a cellular network (as shown in FIG. 1), subscriber stations (SS) access a base station by sharing wireless links, and the base station broadcasts information to every subscriber station through the wireless links.
In the prior art, bandwidth allocation methods for general cellular networks are all based on the following supposition: bandwidth allocation for uplink traffic is independent of bandwidth allocation for downlink traffic. This supposition is reasonable to the above cellular networks, such as 802.16 networks or UMTS/W-CDMA networks. Since uplink traffic resources do not have a direct bearing on downlink traffic resources in general cellular networks, uplink bandwidth allocation and downlink bandwidth allocation are performed on the basis of uplink traffic resources and downlink traffic resources respectively and independently.
However, the traditional allocation method, namely independent allocation of uplink and downlink bandwidth, does not apply to wireless single-hop self-backhaul networks.
FIG. 2 shows a wireless single-hop self-backhaul network. The network comprises a base station (BS), a plurality of subscriber stations (SS) and a backhaul station (BHS). The base station (BS) and the plurality of subscriber stations form a wireless cellular network in a traditional sense, the base station is connected with each of the subscriber stations and the backhaul station via wireless links, and BHS accesses the Internet through a wired link. Wherein, wireless self backhaul means that in the wireless communication network, the base station transmits backhaul transactions with the backhaul station through its own radio resources (frequency, sub-band, slot, etc.).
Apparently, the wireless self-backhaul network differs from the traditional cellular network in that the base station does not access the Internet directly through a wired link any more, but it accesses the Internet through a wireless link provided by the backhaul station as its subscriber stations. Therefore, the backhaul station not only provides a wireless link for BS to access the Internet but also receives radio resources allocated by BS as a subscriber station of BS.
This importantly difference makes the traditional bandwidth allocation method unsuitable for wireless single-hop self-backhaul networks. Main problems are as follows: when the traditional bandwidth allocation method is applied to the network, if a sum of uplink and downlink traffic bandwidth exceeds a given threshold (i.e. network overload), the system bandwidth utilization ratio will decrease sharply with the increase in network overload; meanwhile, bandwidth fairness of uplink and downlink traffic for asymmetric service will be utterly destroyed.
Therefore, we need a new bandwidth allocation method for wireless self-backhaul networks in order to solve the above problems, so that a high bandwidth utilization ratio can be achieved and uplink and downlink bandwidth fairness for asymmetric service can be ensured.